ML19309H799
| ML19309H799 | |
| Person / Time | |
|---|---|
| Site: | Marble Hill |
| Issue date: | 05/08/1980 |
| From: | James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| To: | Shields S PSI ENERGY, INC. A/K/A PUBLIC SERVICE CO. OF INDIANA |
| References | |
| NUDOCS 8005190733 | |
| Download: ML19309H799 (1) | |
Text
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fo UNITED STATES 4
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e NUCLEAR REGULATORY COMMISSION g
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'c. c REGION 111 e-e'['
799 ROOSEVELT ROAD o,
GLEN ELLYN,ILLINOls 60137 Docket No. 50-546 Docket No. 50-547 Public Service of Indiana ATTN:
Mr. S. W. Shields i
Vice President - Electric System 1000 East Main Street Plainfield, IN 46168 Gentlemen:
The enclosed Information Notice provides early notification of an event that may have safety significance. Accordingly, you should review the Information Notice for possible applicability to your facility.
l No specific action or response is requested at this time; however, con-tingent upon the results of further staff evaluation, a Bulletin or Circular recommending or requesting specific licensee actions may be issued.
If you have questions regarding this matter, please contact me.
Sincerely, i
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[%=2 b f^f1Fr James G. Kep Director
Enclosure:
IE Information Notice No. 80-20 cc w/ encl:
Mr. Steve J. Brewer, Nuclear Safety and Licensing Supervisor Central Files Director, NRR/DPM Director, NRR/ DOR PDR Local PDR l
NSIC TIC LeBoeuf, Lamb, Leiby & MacRae Mr. Dave Martin, Office of the Attorney General Mr. John R. Galloway, Staff Director, Environment, Energy and Natural Resources Subcommittee i
I l
SSINS No.:
6870 UNITED STATES Accession No.:
i NUCLEAR REGULATORY COMMISSION 8002280671 0FFICE OF INSPECTION AND ENFORCEMENT l
WASHINGTON, D. C. 20555 May 8, 1980 1
IE Information Notice 80-20 LOSS OF DECAY HEAT REMOVAL CAPABILITY AT DAVIS-BESSE UNIT 1 WHILE IN A REFUELING MODE 1
Description of Circumstances:
1 On April 19, 1980, decay Neat removal capability was lost at Davis-Besse Unit 1 for approximately two and one-half hours.
At the time of the event, the unit was in a refueling mode (e.g., RCS temperature was 90F; decay heat was being removed by Decay Heat Loop No. 2; the vessel head was detensioned with bolts in place; the reactor coolant level was slightly below the vessel head flanges; and the manway covers on top of the once through steam generators were removed).
(See Enclosure A, Status of Davis-Besse 1 Prior to Loss of Power to Busses E-2 and F-2 for additional details regarding this event.)
Since the plant was in a refueling mode, many systems or components were out of service for maintenance or testiag purposes.
In addition, other systems and components were deactivated to preclude their inadvertent actuation while in a refueling mode.
Systems and components that were not in service or deactivated included:
Containment Spray System; High Pressure Injection System; Source Range Channel 2; Decay Heat Loop No. 1; Station Battery IP and 1N; Emergency Diesel-Generator No. 1; 4.16 KV Essential Switchgear Bus C1; and 13.8 KV Switchgear Bus A (this bus was energized but not aligned).
In brief, the event was due to the tripping of a non-safeguards feeder breaker in 13.8 KV Switchgear Bus B. Because of ti.e extensive maintenance and testing activities being conducted at the time, Channels 1 and 3 of the Reactor Protec-tion System (RPS) and Safety Features Actuation System (SFAS) were being ener-gized from only one source, the source emanating from the tripped breaker.
Since the SFAS logic used at Davis-Besse is a two out of-four input scheme in which the loss (or actuation) of any two input signals results in the actuation of all four output channels (i.e., Channels 1 and 3 and Ch loss of power to Channels 1 and 3 bi Channels 2 and 4.
The actuation of Decay Heat Loop No. 2, the operatin DUPMCATE DOCUMENT Since the initiating event was a los were actuated (i.e., level 1 - High Entire document previous 1 tion; Level 3 - Low Pressure Injecti entered into system un ANO OO N
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